Computer graphics processing and selective visual display system – Display peripheral interface input device – Touch panel
Reexamination Certificate
1999-05-06
2001-09-18
Nguyen, Chanh (Department: 2775)
Computer graphics processing and selective visual display system
Display peripheral interface input device
Touch panel
C345S168000, C345S179000
Reexamination Certificate
active
06292179
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a software keyboard system using a touch screen, and more particularly, to a software keyboard system in which a plurality of key codes are assigned to one key, and using the trace of a stylus moving on a key displayed on a touch screen, a key code is generated, and to a method for recognizing a key code using the same. Here, “stylus” is used as a general term for any object which, when pressed onto a touch screen, can cause an input to a computer system or the like.
2. Description of the Related Art
In a small-sized personal computer (PC) such as an electronic organizer or a palm PC, it is difficult to input information. That is, since a small area of the keyboard must include a multitude of keys, the size of the key must be reduced, and thus it is difficult to rapidly and accurately input information using the keys.
To solve the above problems, software keyboards using a touch screen are being widely used.
According to U.S. Pat. No. 4,725,694 in which a central processing unit (CPU) displays an image of a complete keyboard on a screen where a touch panel is attached, the CPU recognizes the position of the touch panel pressed by a user, and operates to generate a code for a key corresponding to the position.
However, in the U.S. Pat. No. 4,725,694, since the size of the screen where the entire keyboard is displayed is small, the size of the keys is also small so that it is difficult to accurately select keys, and the surface of the typical touch panel is slippery, thereby resulting in undesired key selection.
Also, according to U.S. Pat. No. 5,612,719, the CPU displays a gesture button image on a screen where a touch panel is attached, and then the touch panel is pressed or moved on by a pen, allowing various operation modes according to the movement of the pen. That is, there are various operation modes in accordance with whether the stylus is placed on the screen or not, and whether a pop-up menu is displayed on the screen.
However, in order to select function from a pop-up menu, a two-step input process is required in which a pop-up menu is displayed, and then a desired menu is selected from the pop-up menu.
SUMMARY OF THE INVENTION
To solve the above problems, it is a first objective of the present invention to provide a software keyboard system using the trace direction of a stylus, in which a key includes a plurality of key codes, and thus one key code is selected in accordance with the trace of the stylus drawn on the key.
It is a second object of the present invention to provide a method for recognizing a key code in accordance with the keyboard system.
To achieve the first objective, there is provided a software keyboard system using a touch screen, comprising:
a screen for displaying a keyboard image or other information;
a touch panel formed of a transparent material covered on the screen, for generating a coordinate value in accordance with a position pressed by a stylus;
an analog-to-digital (AID) converter for converting an analog coordinate value generated by the touch panel to a digital coordinate value;
a memory for storing names of keys forming a keyboard image displayed on the screen and direction range information of a plurality of key codes assigned to each of keys; and
a controller for displaying the keyboard image formed by the key names on the screen, receiving a digital value for the trace of the stylus output from the analog-to-digital (A/D) converter to retrieve a position of the stylus and a direction of the trace, reading a key code from the memory according to the stylus position and the trace direction, and outputting the key code.
The controller displays an image of the generated key code for a predetermined time to distinguish the image from images of other key codes, and then restores the image to its original state.
The memory includes a key information table which stores names of keys to be displayed on the screen as a keyboard image and an address information in which on key codes assigned to each key is stored, and a key code table which stores a direction range information on each of key codes assigned to a key, a key displayed on the screen as the keyboard image has two or more key codes each of which has direction range information different from each other, and the direction range information of the key code refers to a minimum value and a maximum value of the trace direction of the stylus.
To achieve the second objective, there is provided a method for recognizing key codes, in a software keyboard system using a touch panel, comprising the steps of:
(a) displaying an image of a keyboard;
(b) obtaining the trace of a stylus;
(c) determining a key area in which the trace of the stylus is drawn;
(d) obtaining a trace direction of the stylus drawn on the determined key area; and
(e) searching key code information in accordance with the trace direction to generate a key code corresponding to the searched key code information.
It is preferable to further comprise the step of displaying an image of the key code generated by step (e) to be distinguished from other key codes, and then restoring the image to its original state.
The step (b) of obtaining the trace of the stylus, comprises the steps of: (b1) obtaining a coordinate value of a start point in which the stylus contacts a touch panel; (b2) obtaining a coordinate value in which the stylus contacts the touch panel, after a predetermined time; and (b3) determining whether the point obtained in the step (b2) is an end point, and obtaining the end point.
It is also preferable that in the step (c), it is checked whether all coordinate values of the trace drawn by the stylus are within the range defined as a key area, or a part of coordinate values of the trace drawn by the stylus is within the range defined as a key area.
The step (d) of obtaining the trace direction comprises the steps of: (d1) obtaining a vector composed of coordinate values of a start point and an end point of the stylus trace; (d2) calculating the magnitude of the obtained vector;
(d3) comparing the magnitude of the vector with the magnitude of a reference vector; and (d4) determining the trace direction to be zero if the vector magnitude is smaller than the magnitude of the reference vector, and obtaining the trace direction by calculating an angle between the vector and a reference line if the magnitude of the vector is larger than the magnitude of the reference vector.
In the step (d1) of obtaining the vector, an initial unstable stroke is removed from the trace of the stylus considering a characteristic of the stylus sliding on the touch panel, to obtain the vector.
In the step (d) of obtaining the trace direction, a trace of the stylus is divided into a plurality of vectors each of which includes coordinate values of a start point and an end point of each partial trace, and has a weight value proportional to the magnitude thereof, and a trace direction of the stylus is obtained by an average of the weighted vectors.
REFERENCES:
patent: 4310839 (1982-01-01), Schwerdt
patent: 4440513 (1984-04-01), Kataoka et al.
patent: 5376947 (1994-12-01), Kuroda
patent: 5956021 (1999-09-01), Kubota et al.
patent: 0 660 218 (1995-06-01), None
patent: 9-81320 (1997-03-01), None
patent: WO 97/30386 (1997-08-01), None
Anyaso Uchendu O.
Nguyen Chanh
Samsung Electronics Co,. Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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